In-plane anisotropy of transport coefficients in electronic nematic states: Universal origin of nematicity in Fe-based superconductors

The origin of the electronic nematicity and its remarkable material dependence are famous longstanding unsolved issues in Fe-based superconductors. To attack these issues, we focus on the in-plane anisotropy of the resistivity: In the nematic state in FeSe, the relationp(x) >p(y) holds, whereP(x)(y) is the resistivity along the longer (shorter) Fe-Fe axis. In contrast, the opposite anisotropy p(x) < p(y) is realized in other undoped Fe-based superconductors. Such nontrivial material dependence is naturally explained in terms of the strongly orbitaldependent inelastic quasiparticle scattering realized in the orbital-ordered state. The opposite anisotropy between FeSe (p(x) >p(y)) and other undoped compounds (P-x < P-y) reflects the difference in the number of hole pockets. We also explain the large in-plane anisotropy of the thermoelectric power in the nematic state.

This is an article published by American Physical Society